1. Field of the Invention
The present invention pertains to penetrating instruments for penetrating walls of anatomical cavities and, more particularly, to penetrating instruments having retractable penetrating members and/or safety members biased to an extended protruding position such that tissue and organ structures are protected from the tips of the penetrating members. The present invention also pertains to penetrating instruments having anchoring members to automatically anchor the penetrating instruments upon penetration into anatomical cavities.
2. Discussion of the Prior Art
Penetrating instruments are widely used in medical procedures to gain access to anatomical cavities ranging in size from the abdomen to small blood vessels, such as veins and arteries, epidural, pleural and subarachnoid spaces, heart ventricles and spinal and synovial cavities. Use of penetrating instruments has become an extremely popular and important first step in endoscopic, or minimally invasive, surgery to establish an endoscopic portal for many various procedures, such as laproscopic procedures in the abdominal cavity. Such penetrating instruments typically include a cannula or portal sleeve and a penetrating member, such as a trocar, disposed within the cannula and having a sharp tip for penetrating an anatomical cavity wall with the force required to penetrate the cavity wall being dependent upon the type and thickness of the tissue forming the cavity wall. Once the wall is penetrated, it is desirable to protect the sharp tip of the penetrating member from inadvertent contact with or injury to tissue or organ structures in or forming the cavity in that, once penetration is achieved, the lack of tissue resistance can result in the sharp tip traveling too far into the cavity and injuring adjacent tissue or organ structures.
Various safety penetrating instruments have been proposed, generally falling into protruding and retracting categories. In protruding safety penetrating instruments, a safety member is spring-biased to protrude axially beyond the tip of the penetrating member in response to the reduced force on the distal end of the safety member upon entry into the anatomical cavity. The safety member can be disposed around the penetrating member in which case the safety member is frequently referred to as a shield, or the safety member can be disposed within the penetrating member in which case the safety member is frequently referred to as a probe. In retracting safety penetrating instruments, the penetrating member is retracted into the cannula upon entry into the anatomical cavity in response to distal movement of a component of the safety penetrating instrument such as the penetrating member, the cannula, a probe or a safety member such as a shield or probe.
While safety penetrating instruments have been well received, there is room for improvement in minimizing the likelihood of a safety member being extended or a penetrating member being retracted before the cannula has entered the anatomical cavity in that distal movement of a triggering component of the safety penetrating instrument can be induced prematurely if the axial penetrating force applied by the surgeon is irregular or uneven.
Penetrating instruments for establishing communication with anatomical cavities in many various medical procedures and having anchoring members for anchoring the penetrating instruments relative to the anatomical cavities have also been proposed. However, there is room for improvement in this area as well due to the need for intervention by the surgeon to actuate the anchoring members upon penetration into the anatomical cavities.